[20250220] BOJ / 골드4 / 퍼레이드 / 김수연

Author: suyeun84

suyeun84/202502/20 BOJ G4 퍼레이드.md

@@ -0,0 +1,61 @@
+```java
+import java.util.*;
+import java.io.*;
+
+public class Solution {
+	static ArrayList<ArrayList<Integer>> graph;
+	static boolean[] visited;
+	static int V, E;
+	public static void main(String[] args) throws IOException {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		StringTokenizer st = new StringTokenizer(br.readLine());
+		
+		V = Integer.parseInt(st.nextToken());
+		E = Integer.parseInt(st.nextToken());
+		graph = new ArrayList<>(V+1);
+		visited = new boolean[V+1];
+		for (int i = 0; i< V+1; i++) {
+			graph.add(new ArrayList<>());
+		}
+		
+		for (int i = 0; i < E; i++) {
+			st = new StringTokenizer(br.readLine());
+			int a = Integer.parseInt(st.nextToken());
+			int b = Integer.parseInt(st.nextToken());
+			graph.get(a).add(b);
+			graph.get(b).add(a);
+		}
+		connected(1);
+		for (int i = 1; i < V+1; i++) {
+			if (!visited[i]) {
+				System.out.println("NO");
+				return;
+			}
+		}
+		int odd = 0, even = 0;
+		for (int i = 1; i < V+1; i++) {
+			if (graph.get(i).size() % 2 == 1) odd++;
+			else even++;
+		}
+		if ((even == V-2 && odd == 2) || odd == 0) {
+			System.out.println("YES");
+		} else {
+			System.out.println("NO");
+		}
+	}
+
+	static void connected(int idx) {
+		Queue<Integer> q = new LinkedList<>();
+		q.add(idx);
+		visited[idx] = true;
+		while (!q.isEmpty()) {
+			int curr = q.poll();
+			for (int n : graph.get(curr)) {
+				if (visited[n]) continue;
+				visited[n] = true;
+				q.add(n);
+			}
+		}
+	}
+}
+```